Spatiotemporal dynamics of Lutzomyia longipalpis and macro‐habitat characterization using satellite images in a leishmaniasis‐endemic city in Argentina

Abstract

The spatiotemporal population dynamics of Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae) were evaluated in a city in Argentina in which visceral leishmaniasis is endemic. Over 14 sampling sessions, 5244 specimens of five species of Phlebotominae (Diptera: Psychodidae) were captured, of which 2458 (46.87%) specimens were L. longipalpis. Generalized linear models were constructed to evaluate the associations between L. longipalpis abundance and explanatory variables derived from satellite images. The spatial variable 'stratum' and the temporal variable 'season' were also included in the models. Three variables were found to have significant associations: the normalized difference vegetation index; land surface temperature, and low urban coverage. The last two of these were associated with L. longipalpis abundance only during summer and winter, respectively. This variation between seasons supports the development of models that include temporal variables because models of distributions of the abundance of a species may show different critical variables according to the climatic period of the year. Abundance decreased gradually towards the downtown area, which suggests that L. longipalpis responds to a meta-population structure, in which rural-periurban source populations that persist over time may colonize adjacent areas. This information allows for a spatiotemporal stratification of risk, which provides public health authorities with a valuable tool to help optimize prevention measures against visceral leishmaniasis.

Dynamic spatiotemporal modeling of the infected rate of visceral leishmaniasis in human in an endemic area of Amhara regional state, Ethiopia

“…The posterior distributions of covariate effect sizes demonstrate that the mean weekly temperature had a positive association with the infected rate of VLH, This study is in accordance with, the study by [16] in a similar region. Indicates that the outbreak and infection of Visceral leishmaniasis in human (VLH) disease are distributed in the arid and semi-arid parts of the country, high temperatures increase VLH infection rate, this result is in line with the study by [24], [25]. The Average number of Household (ANH) and Average number of Persons Per housing Unit (ANPPHU) had a positive association with the infected the Infected Rate of Visceral Leishmaniasis (VLH).…”

Multiscale environmental determinants of Leishmania vectors in the urban-rural context

“…longiplapis could appear-disappear due to microenvironment changes [42,[57][58][59][60]. Therefore, for modeling the vector "hot spot" abundance along time based on climatic variables (temperature, land surface temperature, and indirect related variables NDVI and NDWI) lag-times and seasonal associations should be considered [47,[61][62][63] instead of same day of capture data. This lag approach could provide a forecasting tool that reflects actual changes in cohorts of vector populations instead of the daily activity.…”

Autochthonous Outbreak of Cutaneous Leishmaniasis due to Leishmania infantum in Corrientes Province, Argentina

“…[22][23][24] Likewise, two cases of L. infantum-caused CL have been described in Paraguay, near the outbreak area discussed here. 25,26 We can speculate on different factors that would influence the appearance of CL because of L. infantum in the urban and periurban areas under study, including a high density of the vector, deficiencies in basic sanitary services (waste management and sanitation), deforestation, activities undermining vector control (inappropriate waste recycling and artisanal brickworks, among others), soil characteristics, the high concentration of families living in poverty and facing difficulties in accessing protection measures, and the presence of dogs infected by L. infantum in the area of study [27][28][29] All of this multicausality could explain the occurrence of the first outbreak of this magnitude in a very dense urban and periurban area.…”

“…3,7,8 Our analysis suggests an urbanization of CL, which is consistent with similar clinical and epidemiological patterns observed in the Mediterranean basin, 30,31 and the presence of good transmission vectors and high prevalence of canine infection, which facilitate the spread of the disease. 28,29 These circumstances could herald a much greater impact and magnitude of CL in the region in the near-to-medium term.…”